chore: upgrade to eslint v8 (#38472)

chore: upgrade to eslint@8

lib/browser/ipc-main-impl.ts

@@ -19,14 +19,14 @@ export class IpcMainImpl extends EventEmitter {
       throw new Error(`Expected handler to be a function, but found type '${typeof fn}'`);
     }
     this._invokeHandlers.set(method, fn);
-  }
+  };
 
   handleOnce: Electron.IpcMain['handleOnce'] = (method, fn) => {
     this.handle(method, (e, ...args) => {
       this.removeHandler(method);
       return fn(e, ...args);
     });
-  }
+  };
 
   removeHandler (method: string) {
     this._invokeHandlers.delete(method);